Thermally-active material assemblies including phase change materials

Abstract

A thermally-activated material assembly transformable between an actuated condition and a non-actuated condition including an actuator material that, in response to being heated and cooled above/below an actuation temperature, causes the actuator element to actuate from a non-actuated shape to an actuated shape, and vice versa, respectively. The assembly also includes a drive mechanism connected to the actuator element and a phase-change material (PCM) associated with the drive mechanism. The drive mechanism causes the PCM to either (i) directly engage the actuator element when the actuator assembly is in the non-actuated condition and to be disengaged from the actuator element when the actuator assembly is in the actuated condition or (ii) directly engage the actuator element when the actuator assembly is in the actuated condition and to be disengaged from the actuator element when the actuator assembly is in the non-actuated condition.

What is claimed is: 
     
       1. A thermally-activated material assembly, transformable between an actuated condition and a non-actuated condition, comprising:
 an actuator element having actuator material defined by an actuation temperature and a reset temperature, wherein the actuator material:
 in response to being heated to or above the actuation temperature, causes the actuator element to actuate from a non-actuated shape, wherein the assembly is in the non-actuated condition, to an actuated shape, transforming the assembly to the actuated condition; and 
 in response to cooling to or below the reset temperature, causes the actuator element to actuate from the actuated shape back to the non-actuated shape; 
 
 a mechanism connected to the actuator element; 
 a phase-change material (PCM) component associated with the mechanism, the PCM component being defined by a phase-change temperature and causing the PCM component to transition from a first state to a second state in response to being heated to or above the phase-change temperature; and 
 a sheath surrounding at least a portion of the PCM component so as to contain material of the PCM component when the PCM component is in the second state; 
 wherein the mechanism is configured and arranged in the assembly to:
 cause the PCM component to directly engage the actuator element when the assembly is in the non-actuated condition and to be disengaged from the actuator element when the assembly is in the actuated condition; or 
 cause the PCM component to directly engage the actuator element when the assembly is in the actuated condition and to be disengaged from the actuator element when the assembly in the non-actuated condition. 
 
 
     
     
       2. The thermally-activated material assembly of  claim 1 , wherein:
 the mechanism is configured to cause the PCM component to directly engage the actuator element when the assembly is in the non-actuated condition and to be disengaged from the actuator element when the assembly is in the actuated condition; and 
 the PCM component is configured so that the phase-change temperature is lower than the actuation temperature of the actuator element and higher than an ambient temperature to which the assembly is expected to be exposed during operation of the assembly. 
 
     
     
       3. The thermally-activated assembly of  claim 1 , wherein;
 the mechanism is configured to cause the PCM component to directly engage the actuator element when the assembly is in the actuated condition and to be disengaged from the actuator element when the assembly is in the non-actuated condition; and 
 the phase-change temperature of the PCM component is lower than the actuation temperature of the actuator element. 
 
     
     
       4. The thermally-activated material assembly of  claim 1 , wherein the PCM component is connected to the mechanism. 
     
     
       5. The thermally-activated material assembly of  claim 1 , wherein the PCM component is an integral part of the mechanism. 
     
     
       6. The thermally-activated material assembly of  claim 1 , wherein the PCM component is a part of a PCM thermal composite including a non-PCM component forming the PCM thermal composite with PCM component, the non-PCM component having a higher conductivity than the PCM component, thereby promoting transfer of heat introduced to a proximal region of the PCM composite to a distal region of the PCM composite during operation of the assembly. 
     
     
       7. The thermally-activated material assembly of  claim 1 , wherein the assembly is designed to effect desired thermal management characteristics when the PCM component is exposed to a heat source being at a temperature that is higher than an ambient temperature to which the assembly is expected to be exposed to during operation of the assembly. 
     
     
       8. The thermally-activated material assembly of  claim 1 , wherein the mechanism biases the assembly toward one of the actuated condition and the non-actuated condition. 
     
     
       9. The thermally-activated material assembly of  claim 1 , wherein the PCM component includes a shape-memory alloy (SMA). 
     
     
       10. The thermally-activated material assembly of  claim 1 , wherein the PCM component includes a shape-memory polymer (SMP). 
     
     
       11. A thermally-activated material assembly, transformable between an actuated condition and a non-actuated condition, comprising:
 an actuator element having actuator material defined by an actuation temperature and a reset temperature, wherein the actuator material:
 in response to being heated to or above the actuation temperature, causes the actuator element to actuate from a non-actuated shape, wherein the assembly is in the non-actuated condition, to an actuated shape transforming the assembly to the actuated condition in response to being heated to the actuation temperature; and 
 in response to cooling to or below the reset temperature, causes the actuator element to actuate from the actuated shape back to the non-actuated shape; and 
 
 a phase-change material (PCM) bath arranged in the assembly adjacent the actuator element so that the actuator element is selectively moved out of, into, and back out of thermal contact with the PCM bath as the actuator element transitions from the actuated condition, to the non-actuated condition, and back to the actuated condition, respectively, wherein:
 the PCM bath is defined by a phase-change temperature; 
 the PCM bath transitions from a first state to a second state in response to being heated to or above the phase-change temperature; and 
 the PCM bath is configured so that the phase-change temperature is lower than the actuation temperature of the actuator element. 
 
 
     
     
       12. The thermally-activated material assembly of  claim 11 , further comprising an enclosure surrounding at least a portion of the PCM bath. 
     
     
       13. The thermally-activated material assembly of  claim 11 , wherein the PCM bath includes a PCM component and a non-PCM component forming a PCM thermal composite with the PCM component, the non-PCM component having a higher conductivity than the PCM component, thereby promoting transfer of heat introduced to the PCM bath in operation of the assembly. 
     
     
       14. The thermally-activated material assembly of  claim 11 , wherein the PCM bath includes a material selected from a group of materials consisting of a shape-memory alloy (SMA) and a shape-memory polymer (SMP). 
     
     
       15. The thermally-activated material assembly of  claim 11 , further including a stop configured and arranged in the assembly to limit strain exerted on the actuator element. 
     
     
       16. A thermally-activated material assembly, transformable between an actuated condition and a non-actuated condition, comprising:
 a thermally-sensitive actuator element having thermally-sensitive actuator material defined by an actuation temperature and a reset temperature, wherein:
 in response to being heated to the actuation temperature, the thermally-sensitive actuator material causes the thermally-sensitive actuator element to actuate from a non actuated shape, wherein the assembly is in the non-actuated condition, to an actuated shape, transforming the assembly to the actuated condition; and 
 in response to being cooled to the reset temperature, the actuator material causes the thermally-sensitive actuator element to actuate from the actuated shape back to the non-actuated shape; and 
 
 a phase-change material (PCM) composite connected to the thermally-sensitive actuator element, the PCM composite including:
 a PCM component defined by a phase-change temperature and causing the PCM component to transition from a first state to a second state in response to being heated to the phase-change temperature; and 
 a non-PCM component distributed with the PCM component, the non-PCM component having a higher conductivity than the PCM component, thereby promoting transfer of heat introduced to a proximal region of the PCM composite to a distal region of the PCM composite; 
 
 wherein the PCM component is configured so that the phase-change temperature is lower than the actuation temperature of the thermally-sensitive actuator element and higher than an ambient temperature to which the assembly is expected to be exposed during operation of the assembly. 
 
     
     
       17. The thermally-activated material assembly of  claim 16 , further comprising a sheath surrounding at least a portion of the PCM composite so as to contain material of the PCM component when the PCM component is in the second state. 
     
     
       18. The thermally-activated material assembly of  claim 16 , wherein the assembly is designed to effect desired thermal management characteristics when the PCM composite is exposed to a heat source being at a temperature that is higher than an ambient temperature to which the assembly is expected to be exposed to during operation of the assembly. 
     
     
       19. A thermally-activated material assembly, transformable between an actuated condition and a non-actuated condition, comprising:
 a thermally-sensitive actuator element having thermally-sensitive actuator material defined by an actuation temperature and a reset temperature, wherein:
 in response to being heated to the actuation temperature, the thermally-sensitive actuator material causes the thermally-sensitive actuator element to actuate from a non-actuated shape, wherein the assembly is in the non-actuated condition, to an actuated shape, transforming the assembly to the actuated condition; and 
 in response to being cooled to the reset temperature, the actuator material causes the thermally-sensitive actuator element to actuate from the actuated shape back to the non-actuated shape; 
 
 a phase-change material (PCM) composite connected to the thermally-sensitive actuator element, the PCM composite including:
 a PCM component defined by a phase-change temperature and causing the PCM component to transition from a first state to a second state in response to being heated to the phase-change temperature; and 
 a non-PCM component distributed with the PCM component, the non-PCM, component having a higher conductivity than the PCM component, thereby promoting transfer of heat introduced to a proximal region of the PCM component to a distal region of the PCM component; and 
 
 a sheath surrounding at least a portion of the PCM composite so as to contain material of the PCM component when the PCM component is in the second state. 
 
     
     
       20. The thermally-activated material assembly of  claim 19 , wherein the PCM component is configured so that the phase-change temperature is lower than the actuation temperature of the thermally-sensitive actuator element. 
     
     
       21. The thermally-activated material assembly of  claim 19 , wherein the PCM component is configured so that the phase-change temperature is higher than an ambient temperature to which the assembly is expected to be exposed during operation of the assembly. 
     
     
       22. The thermally-activated material assembly of  claim 19 , wherein the assembly is designed to effect desired thermal management characteristics when the PCM composite is exposed to a heat source being at a temperature that is higher than an ambient temperature to which the assembly is expected to be exposed to during operation of the assembly.